Have you found a ton of duplicate contacts on Android phone and looking for a quick way to clean up the duplicates? All Android mobile devices come with the Contacts app to help us manage phone numbers. We have checked both LG and HTC phones. The stock Contacts app on them allows users to easily merge and remove duplicate contacts. We will use a LG mobile in this demo to show you how to achieve that.
Unlock your Android phone. Open the Contacts app. Tap the Menu button(three dots) at the top right corner to show the drop-down menu. Then choose Manage contacts.

On the next screen, you can find options to import contacts from storage, back up contacts to phone storage, copy contacts and merge duplicate contacts. Select Merge, then a screen with all duplicate contacts will show up. Preview the duplicate contacts and tap on the Merge button to merge contacts one by one.

Extra Tips
You can merge duplicates in Merge suggestions; restore merged contacts by separating them in Merged contacts tab.